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Posts Tagged ‘mitral stenosis’

PTMC is a revolutionary    interventional cardiology procedure .A fibrosed obstructed  mitral valve is  opened up just like that , with few wires and a balloon  .The procedure  performed within 30 minutes .No  anaesthesia . No surgery .No scar.

Thousands of procedures are done world-wide (Rich countries excluded    they do not have RHD) .We in our institute , have gained considerable experience in PTMC ,  and  have  completed  nearly  200 procedures  in the last  few years .

As we gain experience surprises also galore ! .Suddenly I realised this  funny (At least for me !) phenomenon  from the unique PTMC balloon design.

The other day  , there was an intense argument between two of my  fellows , who were in a dispute  .One was arguing  , the PTMC  balloon  had dilated the tricuspid valve erroneously  while  other was adamant , and  wholesomely convinced  , since the waist  had disappeared it must be the stenotic mitral valve.

The issue came to me  . . .  ended after a nice  debate !

PTMC balloon accura Inoue waist mitral stenosis percutaneous mitral commissurotomy .

Both PTMC balloons  (Inoue ,Accura) are made with innovative design  conceptualized by Japanese genius Kanji Inoue . The balloon has two layers of latex with a nylon mesh sandwiched in between.The latex  is compliant while nylon limits  it  and generates the required pressure .

The balloon is glued in a such a way ,  central part is  constricted  like narrow band .This makes sure the distal part of balloon inflates first , followed by  the proximal and finally the central .This  also help us  to  geographically to fix  the balloon across the narrow mitral valve orifice .

While , we must agree  this a great  concept , there is an an inherent issue when handling a hour glass shaped balloon with a  natural waist .There would  be great deal of confusion when we take disappearing waist as an index of relief of mitral stenosis.

We know ,the key  requirement is that ,  balloon’s waist  should match anatomical MVO .But , it is estimated  exact match  happens in a minority.  The issue gets further complex  with  subvalvular disease , double mitral orifice, eccentric orifices . The efficacy of PTMC is also determined by the appropriate contact of the balloon’s various pressure points . ( It is a balance of intra balloon pressure(3-4 ATMs)  and  the surrounding tissue pressure !)

Disappearing waists is not synonymous with opening  MVOs .All PTMC balloon inflations will shrug of the waist at peak inflation wherever you inflate .(Intra chamber inflations included !)

Final message

Please realise ,  falling pressure gradients and echo  documentation of  MVO  rules supreme  in assessing successful PTMC. Often times , disappearing waist  is  meagerly an optical  Illusion or gratification.

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mid diastolic murmur

mid diastolic murmur in  sinus rhythm

With the onset of Atrial fibrillation

  1. The  first heart sound becomes variable in Intensity (Soft to loud in pliable valve / Soft to softer in calcified valve )
  2. Opening snap continue to occur as long as the  valves are  pliable and noncalcified  .The timing may vary but Intensity remain same .
  3. A 2-OS interval is usually less influenced by AF  as it is primarily determined by mean LA pressure at the onset of diastole which has little variation beat to beat .
  4. Length of the diastolic murmur varies . In Short cycles  MDM  can be  very brief  or even in audible.
  5. In long cycles MDM will be distinct.
  6. A late diastolic murmur in long cycle indicates severe MS.
  7. Even pre-systolic accentuation may be appreciable in some of the long cycles .

Link  to  Echo Image of  Mitral stenosis .

https://www.youtube.com/watch?v=3qvOMwOshg4

How to assess the severity of  MS in the presence of AF ?

  1. Presence of AF by itself indicate presence of severe MS  in most .
  2. A2-OS interval  may be useful
  3. Concentrate on long cycle .Look for ( rather listen !)  for late diastolic component of  MDM .If  you hear it ,  MS is usually severe

Other signs  are often useful

Low volume pulse

Inconspicuous LV impulse

Presence  of  any significant Pulmonary hypertension

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Rheumatic heart disease is rampant in India.  Advanced forms of mitral stenosis are  still common.

Critical mitral stenosis with LA clot formation is often seen.

But here is a  women in late twenties  presenting for the first time with syncope .

And what  you see inside is  not a fiction  . . .

Left atrial clot occupying the whole cavity ! Where is the blood bound for left ventricle ?

4 chamber view

Luckily the clot is   so  big and MVO is less than 1 sq cm. It is highly unlikely the LA clot can negotiate the orifice.

Small fragments can dislodge .This patient developed syncope whenever she bends and lie down at a particular position.

What needs to be done in this patient  ?

Can it be lysed ? No ,Emergency surgery is required with concomitant mitral valvotomy or mitral valve replacement.

Is there a temporary aortic filter available to prevent systemic emboli from heart  ?

Distal protection devices are  available only temporarily in the coronaries and  carotids during interventional procedures.There is no aortic protection devices  for LA,LV clots in high risk patients .  When IVC filters  are used  block a potential pulmonary   clot why not aortic filters  for preventing systemic emboli  ?

Why we have not thought about  this  . . . is  surprising . May be intensive anti coagulation is as effective .

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Planimetery is the age old method to measure the mitral valve  area( MVA) by echocardiography.

Advantage

  • Simple modality
  • 2D echo  is enough
  • Doppler errors avoided
  • In the presence of MR, planimetery orifice has an edge over other methods

Disadvantage

  • Optimal gain setting becomes  important .There is  significant inter and intra observer variability.
  • Shape of the orifice is not constant  ( MVO is funnel like) . Narrowest diameter is usually measured.
  • Planimetery is  a purely an anatomical orifice,while blood flows through both primary and secondary mitral orifices .Sub valvular fusion makes secondary MVO the  narrowest point  . Measuring it becomes difficult as it has no defintion of border.
  • Gross errors possible in calcified valve.
  • In post commissurtomy  the  lateral extent of split is often  not tractable

How to improve the accuracy of planimetery ?

Color Doppler aided  2D  planimetery . This can improve some of the limitations , as  it provides a hemodynamic MVO(Some what physiological ) Of course  , pressure halftime derived MVO is purely a physiological orifice .

Other options to measure MVO

  1. Pressure half time
  2. Continuity equation
  3. PISA method

Advantages and disadvantages  of Pressure half time derived MVO will be posted soon.

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Interventional cardiology has grown leaps and bounds. We are in the era of percutaneous replacement of cardiac valves.  Mitral valvotomy for mitral stenosis is one the stupendous success  stories of interventional cardiology.

In PTMC,  we have a major cardiac valve disease ,  treated without anesthesia  in a  procedure   lasting about 30 minutes and patients  can walk  home within hours of the procedure.

The maximum such procedures are done in developing countries like India, Brazil, and many south Asian , African countries.

It is a procedure requiring continuous  fluroscopy in cath lab. This has been our traditional way of thinking. But now we learn , what we  require is an imaging    modality  for the entry of balloon into IAS and the stenotic  mitral valve .This can be Echo, MRI , CT scan etc not necessarily fluroscopy.

Why not echocardiography to guide the balloon in PTMC ?

This question was  answered successfully . Both TTE and TEE are used .Surprisingly   transthoracic  echo , by itself was   sufficient in many patients to complete  a  PTMC.

The following article in JASE (American society of Echocardiography )  opens new avenues for  echocardiography .The work was done in New Delhi India

http://www.onlinejase.com/article/S0894-7317(05)00073-8/abstract

The most surprising conclusion  from this  study is  , it is suggested complications like cardiac tamponade is less likely in echo guided PTMC !  as we are sure  where we re puncturing  and entering .

Advantages

  • Huge cost advantage.
  • Can be practiced in a wider clinical set up
  • Radiation free (Very important advantage  )
  • Live 3D /Echo and MRI are  expected to improve the  feasibility of this modality .

Caution about TTE/TEE guided PTMC.

  • Not every one can do this procedure.
  • Cardiologists who have mastered catheter based PTMC  can only understand the intricacies of  PTMC
  • While catheters can be easily imaged , when the procedure requires finer guidewire manipulations fluro is a must .
  • Currently this procedure should be done with a cath lab  standby
  • Tackling complications may be an issue , but the most dreaded complication cardiac tamponade is more easily recognised by echocardigraphy
  • Special training on this modality is to be strongly encouraged.Such thing is possible only in country like ours where RHD continues to be rampant.

Final message

Cath guided PTMC is considered  the gold standard .But ,  often  we create gold standards with impure gold ! The IAS puncture and mitral valve crossing is the most blinded  procedure in cath lab.

The same job can be done   better , with good   “ocular orientation”  by simple echocardiography

Often  in medicine , a  simple alternate technique   rarely can  compete with a proven  technique .Thus ,  these  techniques are denied wider  application and hence  fail to  prove  it’s worthiness.

Echo guided pericardial aspiration , MRI guided deep thoracic biopsy  are already established non invasive  assisted intervention , soon we can expect many cardiac intervention will be done in radiation free environment.

Unpopular treatment modalities  need not be synonymous with ineffective  and dangerous  forms of treatment.

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                                This is a  hemodynamic concept paper by Libanoff in 1968 published in circulation.This paper elegantly proved that  the rate of fall of pressure across the mitral valve will predict the mitral valve orifice.     This key paper formed the foundation on which  Liv hatle developed the echocardiographic pressure half time .This pressure half time derived mitral orifice area ( 220/PHT) is key parameter world over for assessing  severity of mitral stenosis non invasively .

Click on the link get this article .This article is available free fulltext from circualtion web site

pressure-half-time

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                                  Even as cardiology community is preoccupied with systemic hypertension & CAD  ,  pulmonary arterial hypertension(PAH) is a much neglected , still  an important clinical cardiac problem encountered . The irony is self evident , there are half a dozen methods to grade systemic hypertension not even a single stadardised grading available for pulmonary arterial hypertension. The WHO  working group defined pulmonary hypertension  few decades ago and was not clinically graded .The only grading available is based on  the pulmonary vascular biopsy changes (Heath Edwards) 

                                   Currently PAH management has gone through revolutionary changes. There is an urgent  need for grading  this entity .This will facilitate to  diagnose , manage and assess the efficacy of the currently available treatment.

                                Developing countries like ours have a great number of PAH due to rampant rheumatic heart disease.  A simple study was done in  100 patients with PAH .Bulk of the study population had RHD .Few had primary pulmonary  hypertension .Systolic , diastolic, and mean pressure was assessed by doppler echocardiographic analysis of tricuspid regurgitation (TR) and pulmonary regurgitaion(PR) jets. TR jet provided the systolic PA pressure , PR jet provided mean as well as diastolic PA pressure .TR jet was available in all patients. PR jet was available only in 60 patients .Hence the diastolic andmean PA pressure data has been extrapolated in some  and  was plotted in a scatter diagram. Five equal quintiles were divided. Patients in first  and 2nd quintiles were graded 1   and third  and 4th  quintile were  graded 2 ,  5 th  was graded 3 respectively. From this cut off points for  various grades of PAH were identified .The top 3% of patients  with highest PAP were graded as grade 4 and all of them had supra systemic PAH. 

The following grading is suggested for PAH* 

 *This is a preliminary  attempt to grade PAH. This could be applicable mainly in rheumatic heart disese and primary pulmonary hypertension .Further refining of methodology is  required.PAH grading may be little different in congenital left to right shunts.

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